According to Stanford University Professor Siegfried Hecker, an authority on nuclear weapons, the estimate is based largely on North Korea's access to uranium and plutonium, reports the BBC.

Though sanctions have prevented the nation from acquiring uranium from many outside sources, an aggressive program to enrich supplies of the metal has likely yielded robust results.

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As for plutonium, satellite tracking suggests North Korea has between 70 and 120 pounds on hand and the ability to create roughly 13 pounds more per year.

At this time, long-range missiles are considered beyond North Korea's abilities, but that could change in as little as 5 years.

Hecker said the matter could be in need of diplomacy, "...as much as Washington may find it repugnant to deal with the Kim regime."

RELATED: Weirdest weapons TSA has confiscated:

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The weirdest weapons TSA has confiscated

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The weirdest weapons TSA has confiscated

TSA #TBT January 2007 --- This Los Angeles (LAX) traveler didn’t think his wardrobe through before coming to the airport. In addition to actual firearms, replica firearms (such as this belt buckle) are prohibited, as they can cause alarm in the airport/airplane environment.

This inert grenade novelty item was discovered in a traveler’s carry-on bag at Seattle (SEA). While it is kind of funny, it’s prohibited altogether from both carry-on and checked baggage. So what’s the big deal if it’s inert? First off, we don’t know it’s inert until explosives professionals take a closer look, and that takes time and slows down the line. It can even lead to a complete shutdown and evacuation. Also, imagine the person sitting next to you on the plane pulling this out of their carry-on. No big deal, right? For these reasons, anything resembling a bomb or grenade is prohibited from both carry-on and checked bags. #TSAGoodCatch

A Dallas Love Field (DAL) traveler had these throwing knives in their carry-on bag. All knives are prohibited from carry-on bags, but may be packed in checked baggage. #TSATravelTips

#TSAGoodCatch - This ornate jawbone tomahawk was discovered in a carry-on bag at Salt Lake City (SLC). Jawbone tomahawks (and all other tomahawks) must be packed in checked baggage.

#TSATravelTips - In addition to being a cute cat keychain, this is a punching weapon. Just as with brass knuckles, they’re prohibited from being packed or carried through the checkpoint. This one was discovered this week at the Norfolk International Airport (ORF). You can pack them in your checked baggage.

#TSAGoodCatch - This folding throwing star was discovered in a carry-on bag at the George Bush Intercontinental Airport (IAH). These are prohibited from carry-on bags and should be packed in checked baggage. #Krull

#TSAGoodCatch - This comb dagger was discovered in a carry-on bag at the Lihue Airport (LIH) in Hawaii. Knives are always prohibited in carry-on bags no matter the size. Concealed knives can lead to fines and arrest.

#TSAGoodCatch - This folding knuckle knife was discovered in a carry-on bag at the Chicago O’Hare International Airport (ORD). Both knives and brass knuckles are prohibited from being transported in carry-on bags

#TSAGoodCatch - This #bejeweled lipstick stun gun was discovered in a carry-on bag at the Hartsfield–Jackson Atlanta International Airport (ATL). All stun guns are prohibited from being packed in carry-on bags or carried on your person.

#TSAGoodCatch - This inert anti-tank landmine was discovered in a checked bag at Austin (AUS). If an item looks like a real bomb, grenade, mine, etc., it is prohibited. When these items are found at a checkpoint or in checked baggage, they can cause significant delays because our explosives detection professionals must respond to resolve the alarm. Even if they are novelty items, you are prohibited from bringing them on board the aircraft.

#TBT - May 2014 - This mallet was discovered in a traveler’s carry-on property at the Burlington International Airport (BTV). Items such as sledgehammers and mallets are considered bludgeons and are prohibited from being packed in carry-on bags. Checked baggage is fine.

#TSAGoodCatch - This ice pick concealed inside of a cane was discovered in a traveler’s carry-on property at Newark (EWR). Concealed weapons can lead to fines and arrest.